the code is :
//First,"wt"open the file "TEST"
//then change to "wb" open the file "TEST"


#include <stdio.h>
void main()
{ FILE *fp=fopen("TEST",...);//"wt"
//"wb"
fputc('A',fp);fputc('\n',fp);
fputc('B',fp);fputc('\n',fp);
fputc('C',fp);
fclose(fp);
}


//then the file "TEST" file length is ?

some choice:
A 7byte 7byte
B 7byte 5byte
C 5byte 7byte
D 5byte 5byte

...what?

that's

FILE *fp=fopen("TEST","wt");
FILE *fp=fopen("TEST","wb");

then "TEST" file 's length is?